We propose a continuation of a program of research aimed at the discovery of new tools and tactics for the selective control of insect pests and vectors of disease. In collaboration with two postdoctoral associates the investigation will be carried out on a Drosophila cell line and on the "tobacco hornworm" (Manduca sexta)--a large lepidopteran cultured throughout the year on a synthetic diet. Our central objective is to obtain detailed knowledge of the interactions of the brain, the prothoracic glands, and corpora allata in the hormonal control of insect growth and metamorphosis. Improved understanding of the normal mechanisms may reveal weak spots in the physiological armor of insect pests and vectors of disease.